<?php
/**
 *  $Id$
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

/**
 * Doctrine_Locator
 *
 * @package     Doctrine
 * @subpackage  Doctrine_Locator
 * @category    Locator
 * @license     http://www.gnu.org/licenses/lgpl.txt LGPL
 * @link        http://www.doctrine-project.org
 * @author      Janne Vanhala <jpvanhal@cc.hut.fi>
 * @author      Konsta Vesterinen <kvesteri@cc.hut.fi>
 * @author      Eevert Saukkokoski <dmnEe0@gmail.com>
 * @version     $Revision$
 * @since       1.0
 */
class Doctrine_Locator implements Countable, IteratorAggregate
{
	/**
	 * @var array $_resources       an array of bound resources
	 */
	protected $_resources = array();

	/**
	 * @var string $_classPrefix    the default class prefix
	 */
	protected $_classPrefix = 'Doctrine_';

	/**
	 * @var array $_instances       a pool of this object's instances
	 */
	protected static $_instances = array();

	/**
	 * Constructor. Provide an array of resources to set initial contents.
	 *
	 * @param array
	 * @return void
	 */
	public function __construct(array $defaults = null)
	{
		if (null !== $defaults) {
			foreach ($defaults as $name => $resource) {
				if ($resource instanceof Doctrine_Locator_Injectable) {
					$resource->setLocator($this);
				}
				$this->_resources[$name] = $resource;
			}
		}
		self::$_instances[] = $this;
	}

	/**
	 * instance
	 *
	 * @return Sensei_Locator
	 */
	public static function instance()
	{
		if (empty(self::$_instances)) {
			$obj = new Doctrine_Locator();
		}
		return current(self::$_instances);
	}

	/**
	 * setClassPrefix
	 *
	 * @param string $prefix
	 */
	public function setClassPrefix($prefix)
	{
		$this->_classPrefix = $prefix;
	}

	/**
	 * getClassPrefix
	 *
	 * @return string
	 */
	public function getClassPrefix()
	{
		return $this->_classPrefix;
	}

	/**
	 * contains
	 * checks if a resource exists under the given name
	 *
	 * @return boolean      whether or not given resource name exists
	 */
	public function contains($name)
	{
		return isset($this->_resources[$name]);
	}

	/**
	 * bind
	 * binds a resource to a name
	 *
	 * @param string $name      the name of the resource to bind
	 * @param mixed $value      the value of the resource
	 * @return Sensei_Locator   this object
	 */
	public function bind($name, $value)
	{
		$this->_resources[$name] = $value;

		return $this;
	}

	/**
	 * locate
	 * locates a resource by given name and returns it
	 *
	 * @throws Doctrine_Locator_Exception     if the resource could not be found
	 * @param string $name      the name of the resource
	 * @return mixed            the located resource
	 */
	public function locate($name)
	{
		if (isset($this->_resources[$name])) {
			return $this->_resources[$name];
		} else {
			$className = $name;

			if ( ! class_exists($className)) {

				$name = explode('.', $name);
				$name = array_map('strtolower', $name);
				$name = array_map('ucfirst', $name);
				$name = implode('_', $name);

				$className = $this->_classPrefix . $name;

				if ( ! class_exists($className)) {
					throw new Doctrine_Locator_Exception("Couldn't locate resource " . $className);
				}
			}

			$this->_resources[$name] = new $className();

			if ($this->_resources[$name] instanceof Doctrine_Locator_Injectable) {
				$this->_resources[$name]->setLocator($this);
			}

			return $this->_resources[$name];
		}

		throw new Doctrine_Locator_Exception("Couldn't locate resource " . $name);
	}

	/**
	 * count
	 * returns the number of bound resources associated with
	 * this object
	 *
	 * @see Countable interface
	 * @return integer              the number of resources
	 */
	public function count()
	{
		return count($this->_resources);
	}

	/**
	 * getIterator
	 * returns an ArrayIterator that iterates through all
	 * bound resources
	 *
	 * @return ArrayIterator    an iterator for iterating through
	 *                          all bound resources
	 */
	public function getIterator()
	{
		return new ArrayIterator($this->_resources);
	}
}
